Abstract
A previously fit 39-yr-old man was admitted with clinical findings suggestive of septicaemic shock. Afier routine insertion of a central venous catheter he developed electromechanical dissociation. Prolonged efforts to resuscitate the patient were unsuccessful. Post mortem examination showed a cyst arising from the tricuspid valve annulus which had prolapsed into the right ventricular outflow tract. The insertion of a central venous catheter probably caused the cyst to prolapse and cause cardiac arrest with electromechanical dissociation. This unique complication emphasises the importance of not allowing the Sel-dinger wire or central venous catheter to enter the heart during insertion. Correct positioning of central venous catheters during insertion is most safely confirmed by back flow of blood in the catheter and right atrial electrocardiography together with a follow up chest radiograph, rather than relying on the occurrence of cardiac arrhythmias during placement of the Sel-dinger wire or catheter. To avoid excessive lengths of Seldinger wire or catheter being inserted inadvertently during placement, both should be marked along their lengths.